1. Field of the Invention
The present invention relates to the art of fabricating corrugated board from sheet or web material. More specifically, the present invention relates to a method and apparatus for facilitating the expedient re-assembly of a glue applicator roll into operative position with a corrugating roll.
2. Brief Description of the Prior Art
Corrugated board such as fabricated from paper web is manufactured by forming the length of a medium web into a continuum of transverse undulations, each undulation period being known as a flute. To the crest of each flute, on one surface side of the corrugated medium, is secured, as by adhesive bonding, a flat, liner web.
Subsequently, if desired, a second liner web may be adhered to flute crests of the opposite surface side of the corrugated medium to form what is known as "Double-faced" board.
This lamination process may be repeated as often as desired by alternating a corrugating medium with a liner web to achieve greater strength and thickness, the flute crests of each corrugated medium being adhered to the previously applied liner.
The corrugated medium begins as a flat, fourdrinier laid paper web which is drawn into the nip between two corrugating rolls. Such corrugating rolls are, generally, axially rotating cylinders having a corrugated surface pattern, the corrugation flutes extending parallel with the roll axes.
Two such corrugating rolls are meshed gear-like to form a cooperative, undulating nip into which the medium web is pressure formed to the desired shape.
Upon emerging from the corrugating nip, the "memory" characteristic of the corrugated medium exerts a restoration force to the original, flat configuration that resultantly tends to warp the web. To resist this tendency, guides or stripper fingers are provided to hold the corrugated web tightly to the surface of one corrugating roll upon emerging from the corrugating nip. These fingers extend arcuately around the transfer corrugating roll from the corrugation forming nip to a cooperative nip with a flat surface pressure roll which presses the first liner web into contact with the medium flute crests. Normally, these fingers are spaced approximately two to four inches (50-100 mm) apart thereby requiring 23 to 46 fingers on an 87 inch (2200 mm) machine (web width).
Arcuately intermediate of the corrugation forming nip and the liner pressing nip, adhesive must be applied to the flute crests for the purpose of bonding the medium and liner together.
The usual prior art technique of applying adhesive to the flute crests is by means of a glue station comprising a glue roll rotating adjacent a doctor roll. A chordal portion of the glue roll is immersed in a pool of liquid adhesive to pick up a surface film of the adhesive which is trimmed to a desired thickness by the doctor roll. A portion of the remaining adhesive film on the glue roll is transferred by rotational wiping to the flute crests.
Because the adhesive must be applied to the medium flute crests along the arc between the corrugation forming nip and the liner nip, the glue roll is grooved to accommodate the web depth of the fingers. So as to assure uniform adhesive application to the flute crests between the fingers, these glue roll grooves are as narrow as tolerable. Similarly, the web thickness of the fingers is as narrow as tolerable.
In the production running of a corrugating machine as heretofore described, it is frequently necessary to withdraw the glue station, as a composite assembly from the corrugator, to gain physical access to the finger arc of the corrugating roll. Finger adjustment or machine clearing and cleaning following a jam dictates such necessity.
Due to the close tolerance between the finger and the glue roll grooves as compounded by the multiplicity of such finger-groove combinations, it is an extremely tedious and time consuming task to re-position the glue roll following disengagement.
It is therefore an object of the present invention to teach a method and apparatus whereby the finger grooves of an adhesive application roll may be meshed with all the stripper fingers of a corrugating transfer roll simultaneous with the application roll approach to the corrugating roll.